1. Field of the Invention
The present invention relates to a driving apparatus suited for driving a lens or the like in a mobile telephone with a camera, a small-sized digital camera or the like, and a manufacturing method for the driving apparatus.
2. Description of the Related Art
A driving apparatus, as known in the aforementioned technical field of the related art (as referred to JP-A-2002-142470, JP-A-2007-74889, JP-A-10-337055, and JP-A-2006-311794, for example), comprises: an electromechanical conversion element for expanding and contracting in the extending direction of a given fiducial line; a driving shaft mounted on one end of the electromechanical conversion element in the extending direction of the given fiducial line; a driven member frictionally engaged with the driving shaft; and a holder supporting the electromechanical conversion element and having a bearing hole of the driving shaft.
In these driving apparatus, driving pulses having saw-tooth waveforms are applied to the electromechanical conversion element so that the electromechanical conversion element is deformed in the state where an expanding rate and a contracting rate are different. When the electromechanical conversion element is deformed at a low rate, moreover, the driven member is caused by the friction to stand still with respect to the driving shaft. When the electromechanical conversion element is deformed at a high rate, on the contrary, the driven member is caused by the inertia to move with respect to the driving shaft. By applying the driving pulses having the saw-tooth waveforms repeatedly to the electromechanical conversion element, therefore, the driven member can be intermittently moved at a fine pitch.
At the time of manufacturing the aforementioned driving apparatus, however, a clearance exists between the outer face of the driving shaft and the inner face of the bearing hole. Therefore, an adhesive for supporting the electromechanical conversion element in the holder may be hardened in the state where the driving shaft is inclined with respect to a given fiducial line. An extremely high optical performance is demanded especially for driving a lens or the like in the mobile telephone with the camera, the small-sized digital camera or the like. Therefore, even a small inclination of the driving shaft with respect to the given fiducial line raises a serious problem.